diff --git a/admin/roles/admins.php b/admin/roles/admins.php
index 450d432028e..1f5a8fe7217 100644
--- a/admin/roles/admins.php
+++ b/admin/roles/admins.php
@@ -67,6 +67,26 @@ if (optional_param('add', false, PARAM_BOOL) and confirm_sesskey()) {
         }
     }
 
+} else if (optional_param('main', false, PARAM_BOOL) and confirm_sesskey()) {
+    if ($newmain = $admisselector->get_selected_users()) {
+        $newmain = reset($newmain);
+        $newmain = $newmain->id;
+        $admins = array();
+        foreach(explode(',', $CFG->siteadmins) as $admin) {
+            $admin = (int)$admin;
+            if ($admin) {
+                $admins[$admin] = $admin;
+            }
+        }
+
+        if (isset($admins[$newmain])) {
+            unset($admins[$newmain]);
+            array_unshift($admins, $newmain);
+            set_config('siteadmins', implode(',', $admins));
+            redirect($PAGE->url);
+        }
+    }
+
 } else if ($confirmadd and confirm_sesskey()) {
     $admins = array();
     foreach(explode(',', $CFG->siteadmins) as $admin) {
@@ -115,6 +135,7 @@ echo $OUTPUT->header();
         <p class="arrow_button">
             <input name="add" id="add" type="submit" value="<?php echo $OUTPUT->larrow().'&nbsp;'.get_string('add'); ?>" title="<?php print_string('add'); ?>" /><br />
             <input name="remove" id="remove" type="submit" value="<?php echo get_string('remove').'&nbsp;'.$OUTPUT->rarrow(); ?>" title="<?php print_string('remove'); ?>" />
+            <input name="main" id="main" type="submit" value="<?php echo get_string('mainadminset', 'role'); ?>" title="<?php print_string('mainadminset', 'role'); ?>" />
         </p>
       </td>
       <td id='potentialcell'>
diff --git a/admin/roles/lib.php b/admin/roles/lib.php
index b09ed4f688a..68a3c8bb1c7 100644
--- a/admin/roles/lib.php
+++ b/admin/roles/lib.php
@@ -1584,13 +1584,31 @@ class admins_existing_selector extends user_selector_base {
             return array();
         }
 
-        if ($search) {
-            $groupname = get_string('extusersmatching', 'role', $search);
-        } else {
-            $groupname = get_string('extusers', 'role');
+        $mainadmin = array();
+        $adminids = explode(',', $CFG->siteadmins);
+        foreach ($adminids as $id) {
+            if (isset($availableusers[$id])) {
+                $mainadmin = array($id=>$availableusers[$id]);
+                unset($availableusers[$id]);
+                break;
+            }
         }
 
-        return array($groupname => $availableusers);
+        $result = array();
+        if ($mainadmin) {
+            $result[get_string('mainadmin', 'role')] = $mainadmin;
+        }
+
+        if ($availableusers) {
+            if ($search) {
+                $groupname = get_string('extusersmatching', 'role', $search);
+            } else {
+                $groupname = get_string('extusers', 'role');
+            }
+            $result[$groupname] = $availableusers;
+        }
+
+        return $result;
     }
 
     protected function get_options() {
diff --git a/lang/en/role.php b/lang/en/role.php
index 2bf28ccfee1..971722c4fb2 100644
--- a/lang/en/role.php
+++ b/lang/en/role.php
@@ -212,6 +212,8 @@ $string['legacytype'] = 'Legacy role type';
 $string['legacy:user'] = 'LEGACY ROLE: Authenticated user';
 $string['listallroles'] = 'List all roles';
 $string['localroles'] = 'Locally assigned roles';
+$string['mainadmin'] = 'Main administrator';
+$string['mainadminset'] = 'Set main admin';
 $string['manageadmins'] = 'Manage site administrators';
 $string['manager'] = 'Manager';
 $string['managerdescription'] = 'Managers can access course and modify them, they usually do not participate in courses.';
diff --git a/lib/datalib.php b/lib/datalib.php
index e888b23149d..0b86106e1db 100644
--- a/lib/datalib.php
+++ b/lib/datalib.php
@@ -49,24 +49,32 @@ define('LASTACCESS_UPDATE_SECS', 60);
 
 /**
  * Returns $user object of the main admin user
- * primary admin = admin with lowest role_assignment id among admins
  *
  * @static stdClass $mainadmin
  * @return stdClass {@link $USER} record from DB, false if not found
  */
 function get_admin() {
+    global $CFG, $DB;
+
     static $mainadmin = null;
 
-    if (!isset($mainadmin)) {
-        if (! $admins = get_admins()) {
-            return false;
+    if (isset($mainadmin)) {
+        return clone($mainadmin);
+    }
+
+    foreach (explode(',', $CFG->siteadmins) as $id) {
+        if ($user = $DB->get_record('user', array('id'=>$id, 'deleted'=>0))) {
+            $mainadmin = $user;
+            break;
         }
-        //TODO: add some admin setting for specifying of THE main admin
-        //      for now return the first assigned admin
-        $mainadmin = reset($admins);
+    }
+
+    if ($mainadmin) {
+        return clone($mainadmin);
+    } else {
+        // this should not happen
+        return false;
     }
-    // we must clone this otherwise code outside can break the static var
-    return clone($mainadmin);
 }
 
 /**